| 摘要 |
PROBLEM TO BE SOLVED: To reduce battery consumption by detecting transmission radio waves from a radio base station in a radio terminal and continuously operating a receiver, only at the time of detecting sound signals. SOLUTION: In radio base stations 102-105, a transmitter is normally stopped, and only when reception radio waves from at least one radio terminal 107 are present and sound is received, the transmitter of the radio base station 103 is made to be operated. In the meantime, in the radio terminal 107, the receiver is intermittently operated when the transmission waves and the sound from the radio base stations 102-105 are not received, and only when the transmission radio waves from the radio base station 102-105 are detected and the sound signals are detected at the time of the intermittent operation, the receiver is operated continuously. In such a manner, the radio terminal 107 transmits the radio waves only in the case that the transmission sound is present, the radio waves above a fixed electric field level are received in the radio base station 103, the transmitters for all the radio base stations 102-105 are operated, only in the case that the tone squelch of the sound is operated, and the transmission sound from the radio terminal 107 which performs transmission is transmitted. |
